This section is mainly concerned with the “electrics” in your home, that is, the CONSUMER UNIT, or DISTRIBUTION BOARD (the unit with the large ON/OFF switch), the various combinations of circuit-breakers, or fuse cartridges within it, and the wiring, plugs, and sockets.
Obviously SAFETY is of prime importance when investigating ANY electrical problem, and NO-ONE SHOULD EVER WORK ON LIVE WIRING AT ANY TIME. Again, I will point out the DISCLAIMER on this site.
From time to time, you may need to monitor, say your washing machine, after replacing a drive belt, with the cover off. You must ensure that you are not exposed to, and do NOT TOUCH any exposed wiring or contacts. You will find that most manufacturers have recessed push-on contacts, or plug/socket arrangements for a lot of internal parts of home appliances, but this is by no means consistent and universal.
Always ensure that any appliance you are working on is protected by the correct fuse in the plug, and where possible on a circuit protected by an RCD (used to be called ELCB).
Always ensure you wear rubber soled shoes, and a pair of those “thow-away” rubber gloves (not the see though sort, they are too thin). Motorists discount centres tend to stock those, at around £5 per box. They will keep your hands from getting too grimy anyway, especially if changing motor brushes.
Major appliances like dishwashers, cookers, and washing machines should have the casework connected to earth. Check the earth wire in the plug is sound and properly screwed into the top terminal of the plug BEFORE YOU START ANY WORK OR TESTING WITH CASEWORK REMOVED.
DOUBLE CHECK THE ABOVE - use at least a mains testing screwdriver to see that any metal casework of the appliance you are working on is NOT LIVE. Preferrably use a meter to check between the appliance case and a known good earth point.
If you KNOW your earth bonding is good, and you have NO plastic piping for central heating, then any radiator or pipe SHOULD be a good earth point to do a meter test.
RCD = Residual Current Device. These used to be called Earth Leakage Circuit Breakers. You should have one on your consumer unit. If you have a utility room, with appliances like washing machines or dryers, the should be on a plug ring protected by the RCD, usually rated at 80 AMPS, with 30ma leakage trip current.
They should all have a test switch. You should test it occasionally. Note that it will not always switch back on and click home first time, so try a few times. Some have a round knob that turns clockwise half a turn, others have the traditional circuit breaker trip-lever.
Garage/Workshops should have a seperate one ideally, but many “wired” garages only have a small fused isolator. To increase protection when working in your garage, either fit one “in-line” between the fuse unit and the fused feed, or get a “plug-in” version, that goes into each plug. Note that if the power goes, or you plug these in for the first time, they need a RESET button pressed.
Electric Lawn-mowers are probably one of the most well-known and popular items to protect with an RCD. Certainly with the likelyhood of slicing through the cable, the combination of damp grass etc , a seperate plug-in RCD greatly reduces the risk of shock hazard.